Convert __require back to require for external bundlers

Author: jakebailey

Gulpfile.js

@@ -159,18 +159,16 @@ function getCopyrightHeader() {
  * @param {boolean} performanceMatters True if this is a bundle where performance matters, so should be optimized at the cost of build time.
  */
 function esbuildTask(entrypoint, outfile, exportIsTsObject = false, performanceMatters = false) {
-    const preBabel = `${outfile}.tmp.js`;
-
     /** @type {esbuild.BuildOptions} */
     const options = {
         entryPoints: [entrypoint],
         banner: { js: getCopyrightHeader() },
         bundle: true,
-        outfile: performanceMatters ? preBabel : outfile,
+        outfile,
         platform: "node",
         target: "es2018", // This covers Node 10.
         format: "cjs",
-        sourcemap: true,
+        sourcemap: "linked",
         external: ["./node_modules/*"],
         conditions: ["require"],
         supported: {
@@ -180,6 +178,30 @@ function esbuildTask(entrypoint, outfile, exportIsTsObject = false, performanceM
         // legalComments: "none", // If we add copyright headers to the source files, uncomment.
     };
 
+    if (performanceMatters) {
+        const preBabel = `${outfile}.tmp.js`;
+        options.outfile = preBabel;
+        options.sourcemap = "inline";
+        options.plugins = [
+            {
+                name: "babel",
+                setup: (build) => {
+                    build.onEnd(async () => {
+                        await exec(process.execPath, [
+                            "./node_modules/@babel/cli/bin/babel.js",
+                            preBabel,
+                            "--out-file", outfile,
+                            "--plugins", "@babel/plugin-transform-block-scoping,./scripts/build/removeEsbuildRequire",
+                            "--compact", "false",
+                            "--source-maps"]
+                        );
+                        await del(preBabel);
+                    });
+                },
+            }
+        ];
+    }
+
     if (exportIsTsObject) {
         options.format = "iife"; // We use an IIFE so we can inject the code below.
         options.globalName = "ts"; // Name the variable ts, matching our old big bundle and so we can use the code below.
@@ -200,15 +222,7 @@ function esbuildTask(entrypoint, outfile, exportIsTsObject = false, performanceM
     }
 
     return {
-        build: async () => {
-            await esbuild.build(options);
-            if (performanceMatters) {
-                // TODO(jakebailey): we could use ts.transpileModule for this, but running babel is faster to get this singular transform.
-                // If we did use ts.transpileModule, we'd need ts.ScriptTarget.ES5, which also will downlevel arrow functions, for-of, spread, etc.
-                await exec(process.execPath, ["./node_modules/@babel/cli/bin/babel.js", preBabel, "--out-file", outfile, "--plugins", "@babel/plugin-transform-block-scoping", "--compact", "false", "--source-maps"]);
-                await del([preBabel, `${preBabel}.map`]);
-            }
-        },
+        build: () => esbuild.build(options),
         clean: () => del([outfile, `${outfile}.map`]),
         watch: () => esbuild.build({ ...options, watch: true }),
     };

package-lock.json

@@ -43,6 +43,7 @@
         "@babel/core": "^7.19.3",
         "@babel/plugin-transform-block-scoping": "^7.18.9",
         "@octokit/rest": "latest",
+        "@types/babel__core": "^7.1.19",
         "@types/chai": "latest",
         "@types/fs-extra": "^9.0.13",
         "@types/glob": "latest",

package.json

@@ -0,0 +1,23 @@
+module.exports = () => {
+    /** @type {import("@babel/core").PluginObj} */
+    const plugin = {
+        name: "remove-esbuild-require",
+        visitor: {
+            VariableDeclarator: (path) => {
+                const id = path.node.id;
+                if (id.type === "Identifier" && id.name === "__require") {
+                    path.remove();
+                }
+            },
+            CallExpression: (path) => {
+                // esbuild will transform require to __require, but that may trip up bundlers
+                // run on our own output, so convert them back,
+                const callee = path.node.callee;
+                if (callee.type === "Identifier" && callee.name === "__require") {
+                    callee.name = "require";
+                }
+            },
+        }
+    };
+    return plugin;
+};